Internal combustion engine

ABSTRACT

An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of co-pending, commonly assigned U.S.patent application Ser. No. 11/695,536 filed on Apr. 2, 2007; whichclaims priority from U.S. Provisional Patent Application No. 60/792,995,filed on Apr. 18, 2006 and U.S. Provisional Patent Application No.60/853,095 filed on Oct. 20, 2006, all of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an internal combustion engine.

2. Discussion of Related Art

Internal combustion engines are used to power vehicles and othermachinery. A typical reciprocating internal combustion engine includes abody, a piston, at least one port, at least one valve, a crankshaft(which serves as a drive shaft), and a connecting rod. The body definesa cylinder. The piston is located inside the cylinder so that a surfaceof the piston and a wall of the cylinder define an internal volume. Theport is located in the body, and allows air and fuel into and exhaustgas out of the internal volume. The valve is movable between a firstposition wherein the port is open, and a second position wherein thevalve closes the port. The crankshaft has a bearing section rotatablymounted to the body and an offset throw section. A connecting rod isconnected between the piston and the offset throw section of thecrankshaft, such that reciprocating movement of the piston causesrotation of the offset throw section of the crankshaft about acrankshaft axis.

A reciprocating engine of the above kind typically has a cylinder headthat defines the internal volume together with the surface of the pistonand the wall of the cylinder. Heat is transferred to the cylinder headand conducts through the cylinder head, thereby resulting in energylosses from the internal volume and a reduction in efficiency. One wayof increasing efficiency is by reducing an area of the surface of thepiston and increasing a stroke (a diameter of a circle that the offsetthrow section follows) of the piston. A large stroke results in highforces created on the piston and other components of the engine, so thatthe engine can only be run at lower revolutions per minute with acorresponding reduction in power. Partial-power operation in aconventional combustion engine is also less efficient than full-poweroperation because a gas within the internal volume does not expand andcool down fully during partial-power operation, resulting in arelatively high temperature of the gas when it is exhausted. The heat inthe exhaust gas is an energy loss that results in a reduction inefficiency.

SUMMARY OF THE INVENTION

The invention provides an internal combustion engine, including a bodydefining first and second cylinders in communication with one another,first and second pistons in the first and second cylinders respectively,surfaces of the pistons and walls of the cylinders defining an internalvolume, at least one port in the body to allow air and fuel into andexhaust gas out of the internal volume, first and second drive shafts,each having a bearing section mounted for rotation on a respective driveshaft axis through the body and each having an offset throw section, thefirst piston and offset throw section of the first drive shaft beingconnected and the second piston and the offset throw section of thesecond drive shaft being connected, such that reciprocating movement ofthe first and second pistons increases and decreases a size of theinternal volume between minimum and maximum sizes and causes rotation ofthe offset throw sections of the first and second drive shafts about thedrive shaft axes, the minimum size of the internal volume beingadjustable between a large size for a large power delivery and a smallsize for a small power delivery, and at least one valve mounted to thebody to respectively open and close the port and respectively allow andrestrict flow of at least the air into the internal volume, the valvebeing operable to allow an increased amount of air into the internalvolume during the large power delivery and a decreased amount of airduring the small power delivery for one cycle of the pistons.

The internal combustion engine may further comprise a combustion chambersize-varying mechanism that adjusts a position of the bearing section ofthe second drive shaft relative to the body.

The combustion chamber size-varying mechanism may synchronize rotationof the drive shafts relative to one another.

The combustion chamber size-varying mechanism may include a gear trainof first second, third, and fourth gears, the first and fourth gearsbeing mounted to the first and second drive shafts, respectively, sothat the first and fourth gears rotate together with the first andsecond drive shafts about the first and second drive shaft axes,respectively, and a combustion chamber size-varying carriage that isconnected to the second drive shaft, the carriage being movable torotate the second drive shaft axis about an axis of rotation of thethird gear.

The internal combustion engine may further comprise a valve-controlsystem that adjusts an amount of air that enters the internal volume,more air being provided for the large power delivery, and less air beingprovided for the small power delivery, the valve-control system alsoshifting a phase of air being delivered to the internal volume betweenthe large power delivery and the small power delivery, relative to aphase of the first drive shaft.

The valve-control system may include a support structure, a carriagemounted for movement to the support structure, a cam rotatably mountedto the carriage and having an outer cam surface, a first follower heldby the support structure, the first follower having an end surfaceagainst fee cam surface so that rotation of the cam causes translationof the first follower, the first follower having a side cam surface, anda second follower having a following surface against the side camsurface so that translation of the first follower causes movement of thesecond follower.

The internal combustion engine may further comprise a sleeve valve, atleast partially around the first piston and being movable between afirst position wherein the port is open and a second position whereinthe sleeve valve closes the port.

The sleeve valve may move in a primarily linear reciprocating pathbetween the first position, where the port is open, and the secondposition, where the sleeve valve closes the port.

The port may have a mouth with a seat and the sleeve valve has a surfaceat an angle other than zero degrees relative to a direction that thesleeve valve travels, the end surface engaging with the seat to closethe port.

The internal combustion engine may further comprise a valve-coolingpiece that, together with an outer surface of the sleeve valve, definesa valve-cooling passage through which a valve-cooling fluid can pass tocool the sleeve valve.

The invention also provides an internal combustion engine, including abody defining first and second cylinders in communication with oneanother, first and second pistons in the first and second cylindersrespectively, surfaces of the pistons and walls of the cylindersdefining an internal volume, at least first and second ports in the bodyto allow air and fuel into and exhaust gas out of the internal volume,first and second sleeve valves at least partially around the first andsecond pistons respectively, the first sleeve valve being movablebetween a first position where the first port is open and a secondposition where the first sleeve valve closes the first port and feesecond sleeve valve being movable between a first position where thesecond port is open and a second position where the second sleeve valvecloses the second port, and first and second drive shafts, each having abearing section rotatably mounted to the body and each having an offsetthrow section, the first piston and the bearing section of the firstdrive shaft being connected such that reciprocating movement of thefirst piston causes movement of the offset throw section of the firstdrive shaft about a first drive shaft axis, and the second piston andthe bearing section of the second drive shaft being connected such thatreciprocating movement of the second piston causes movement of theoffset throw section of the second drive shaft about a second driveshaft axis.

The invention further provides an internal combustion engine, includinga body defining first and second cylinders, first and second pistons inthe first and second cylinders respectively, surfaces of the pistons andwalls of the cylinders defining an internal volume, at least one port inthe body to allow air and fuel into and exhaust gas out of the internalvolume, and first and second drive shafts, each having a bearing sectionrotatably mounted to the body and each having an offset throw section,the first piston and offset throw section of the first drive shaft beingconnected and the second piston and the offset throw section of thesecond drive shaft being connected such that reciprocating movement ofthe first and second pistons causes rotation of the offset throwsections of the first and second drive shafts about drive shaft axes ofthe first and second bearing sections respectively, a distance betweenthe drive shaft axes being adjustable to adjust a minimum size of theinternal volume.

The invention further provides a valve-control system, including asupport structure, a valve-control carriage mounted for movement to thesupport structure, a cam rotatably mounted to the carriage and having anouter cam surface, a first follower held by the support structure, thefirst follower having an end surface against the cam surface so matrotation of the cam causes translation of the first follower, the firstfollower having a side cam surface, and a second follower having afollowing surface against the side cam surface so that translation ofthe first follower causes movement of the second follower.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a piston in the cylinder, a surface of thepiston and a wall of the cylinder defining an internal volume, at leastone port in the body to allow air and fuel into and exhaust gas out ofthe internal volume, a sleeve valve at least partially around the pistonand being movable in a primarily linear reciprocating path between afirst position where the port is open and a second position where thesleeve valve closes the port, and a drive shaft having a bearing sectionrotatably mounted to the body and an offset throw section, the pistonand the offset throw section of the drive shaft being connected suchthat reciprocating movement of the piston causes rotation of the offsetthrow section of the drive shaft about a crankshaft axis of the driveshaft.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a piston in the cylinder, a surface of thepiston and a wall of the cylinder defining an internal volume, at leastone port in the body to allow air and fuel into and exhaust gas out ofthe internal volume, a sleeve valve at least partially around the pistonand being movable between a first position where the port is open and asecond position where the sleeve valve closes the port, an oilpath-defining piece adjacent to the sleeve valve, surfaces of the oilpath-defining piece and the sleeve valve defining an oil passage, an oilinlet port through the body into the passage, an oil outlet port fromthe oil passage through the body, and a drive shaft having a bearingsection rotatably mounted to the body and an offset throw section, thepiston and the offset throw section of the drive shaft being connected,such that reciprocating movement of the piston causes rotation of theoffset throw section of the drive shaft about a drive shaft axis of thedrive shaft.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a piston in the cylinder, a surface of thepiston and a wall of the cylinder defining an internal volume, at leastone port in the body to allow air and fuel into and exhaust gas out ofthe internal volume, the port having a mouth with a seat, a sleeve valveat least partially around the piston and being movable between a firstposition where the port is open and a second position where the sleevevalve closes the port, the sleeve valve having an end surface at anangle other than zero degrees relative to a direction that the sleevevalve travels, the end surface engaging with the seat to close the port,and a drive shaft having a bearing section rotatably mounted to the bodyand an offset throw section, the piston and the offset throw section ofthe drive shaft being connected such that reciprocating movement of thepiston causes rotation of the offset throw section of the drive shaftabout a drive shaft axis.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a fuel supply cavity, and a fuel outlet portconnecting the fuel supply cavity to the cylinder, a piston in thecylinder, a surface of the piston and a wall of the cylinder defining aninternal volume, at least one air inlet port in the body to allow airinto the internal volume, a valve which is movable between a firstposition, wherein the air inlet port and fuel outlet port are open, anda second position where the valve closes the air inlet port and fueloutlet port, and a drive shaft having a bearing section rotatablymounted to the body and an offset throw section, the piston and theoffset throw section of the drive shaft being connected such thatreciprocating movement of the piston, causes rotation of the offsetthrow section of the drive shaft about a drive shaft axis.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a piston held in the cylinder such that aninternal volume is defined by a wall of the cylinder and a surface ofthe piston, at least one port in the body, to allow air and fuel intothe internal volume and exhaust gas out of the internal volume, a driveshaft having a bearing section rotatably mounted to the body and anoffset throw section, the piston and the offset throw section of thedrive shaft being connected such that reciprocating movement of thepiston causes rotation of the offset throw section of the drive shaftabout the drive shaft axis of the drive shaft, a valve which is movablebetween a first position where the port is open and a second positionwhere the valve closes the port, a component connected to the sleevevalve, the component having a surface which, when pressure is appliedthereto, moves the valve into the second position, a valve-pressurereservoir, having a side piece, a spring connected to the side piece andacting on the side piece to maintain an elevated pressure within thevalve-pressure reservoir, a high-pressure reservoir containing fluid ata higher pressure than the valve-pressure reservoir, and a valve that ismovable between a first position wherein the high-pressure reservoir isconnected to the surface and the valve-pressure reservoir isdisconnected from the surface, and a second position wherein thehigh-pressure reservoir is disconnected from the surface and tirevalve-pressure reservoir is connected to the surface.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a piston in the cylinder, surfaces of thepiston and walls of the cylinder defining an internal volume, at leastone port in the body to allow air and fuel into and exhaust gas out ofthe internal volume, a drive shaft having a bearing section mounted forrotation on a drive shaft axis through the body, and having an offsetthrow section, the piston and the offset throw section of the driveshaft being connected such that reciprocating movement of the pistonincreases and decreases a size of the internal volume between minimumand maximum sizes and causes rotation of the offset throw section of thedrive shaft about the drive shaft axis, and a knock sensor to detectpre-ignition within the internal volume, and a feedback system thatadjusts the minimum size of the internal volume based on pre-ignitiondetected by the knock sensor.

The invention further provides an internal combustion engine, comprisinga body defining a cylinder, a piston in the cylinder, surfaces of thepiston and walls of the cylinder defining an internal volume, at leastone port in the body to allow air and fuel into and exhaust gas out ofthe internal volume, a drive shaft having a bearing section mounted forrotation on a drive shaft axis, and having an offset throw section, thepiston and the offset throw section of the drive shaft being connected,such that reciprocating movement of the piston increases and decreases asize of the internal volume between minimum and maximum sizes, andcauses rotation of the offset throw section of the drive shaft about thedrive shaft axis, first and second spark plugs, having first and secondelectrodes respectively, and an ignition system connected between thefirst and second electrodes, the ignition system providing a positivevoltage on the first electrode and a negative voltage on the secondelectrode, such that a voltage differential is created between the firstand second electrodes to create a spark within die internal volume.

The invention further provides an internal combustion engine, includinga body defining a cylinder, a piston, held in the cylinder such that aninternal volume is defined by a wall of the cylinder and a surface ofthe piston, at least one port in the body to allow air and fuel into theinternal volume and exhaust gas out of the internal volume, a driveshaft bearing on the body, a drive shaft having a bearing sectionmounted for rotation, to the drive shaft bearing, and an offset throwsection that moves in a circular path about an axis of the drive shaftbearing, and a connecting rod having first and second ends connected tothe piston and the offset throw section of the drive shaft,respectively, such that reciprocating movement of the piston due tocombustion of the fluid in the internal volume causes movement of theoffset throw section of the drive shaft in the circular path.

The invention further provides an internal combustion engine, includinga body defining a cylinder, at least one piston, a surface of the atleast one piston and a wall of the cylinder defining an internal volume,at least one port in the body to allow air and fuel into and exhaust gasout of the internal volume, and a drive shaft having a bearing sectionrotatably mounted to the body and an offset throw section, the pistonand the offset throw section of the drive shaft being connected, suchthat reciprocating movement of the piston causes rotation of the offsetthrow section of the drive shaft about a drive shaft axis of the driveshaft, wherein during an intake stroke of the at least one piston thesaid at least one valve remains open to allow air into the combustionchamber for a first preselected length of the intake stroke, and duringan expansion stroke of the at least one piston, the said at least onevalve maintains the combustion chamber substantially closed for a secondlength of the expansion stroke, the second length being more than thefirst length, and wherein energy that is transferred through the atleast one piston to a drive train and with energy losses in an exhaustcycle of the at least one piston together are more than 65% of energy ofthe fuel in the cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described by way of example with reference to theaccompanying drawings, wherein:

FIG. 1 is a perspective view of an internal combustion engine, accordingto an embodiment of the invention;

FIG. 2 is a cross-sectional side view of a right valve arrangement, aright casting, and a central connecting piece forming part of the engineof FIG. 1;

FIG. 3 is a cross-sectional side view of components shown in FIG. 2where fuel enters into an internal volume of the engine;

FIG. 4 is an end view illustrating the positioning of spark plugs of theengine;

FIG. 5 is a schematic side view illustrating the assembly ofpower-delivery arrangements and a combustion chamber size-varyingmechanism of the engine;

FIG. 6 is a schematic side view Illustrating a valve-control system ofthe engine;

FIG. 7 is a graph illustrating functioning of the valve-control systemof FIG. 6;

FIGS. 8A through 8G are cross-sectional side views illustratingfull-power operation of the engine;

FIGS. 9A through 9G are cross-sectional side views illustratingpartial-power operation of the engine;

FIGS. 10A and 10B are schematic side views illustrating a hydraulichold-closed system forming part of the engine;

FIG. 11 is a block diagram of a control system forming part of tireengine;

FIGS. 12A and 12B are side views of a combustion chamber size-varyingcarriage used in one alternative embodiment of an internal combustionengine of the invention;

FIGS. 13A and 13B are side views of a combustion chamber size-varyingcarriage used in an further alternative embodiment of an internalcombustion engine of the invention; and

FIG. 14 is a cross-sectional side view illustrating the use of aflexible bellow seal used in an internal combustion engine according toa further embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 of the accompanying drawings illustrates components of aninternal combustion engine 10, according to an embodiment of theinvention, including a body 12, left and right valve arrangements 14 and16, components of a valve-control system 18, spark plugs 20, left andright power delivery arrangements 22 and 24, respectively, and acombustion chamber size-varying mechanism 26.

The body 12 includes a base portion 28, left and right castings 30 and32, and a central connecting piece 34. The left and right castings 30and 32 are mounted to the central connecting piece 34. The assembly,including the left and right castings 30 and 32 and the centralconnecting piece 34, is then secured to the base portion 28 to form aunitary piece with the base portion 28, the castings 30 and 32 and thecentral connecting piece 34 being immovably connected to one another.

As shown in FIG. 2, the right casting 32 includes a cylinder blockportion 36, an air intake and distribution portion 38, and a crankshafthousing 40. The cylinder block portion 36 has a circular bore 42machined from right to left therein. The air intake and distributionportion 38 forms a volute 44 around a left section of the cylinder blockportion 36. The volute 44 has an inlet 46 at the top. Left ends of thecylinder block portion 36 and the air intake and distribution portion 38form a circumferential outlet 48 out of a left side of the volute 44.

The crankshaft housing 40 is an extension from the cylinder blockportion 36, and is larger in size than the cylinder block portion 36.One of two drive shaft openings 50 is shown in the cross-section of FIG.2.

The right valve arrangement 16 includes an oil path-defining piece 52, asleeve valve 54, and a retaining piece 56.

The oil path-defining piece 52 is inserted from right to left into thecircular bore 42. The oil path-defining piece 52 is formed into avalve-cooling portion 58 on the left, and a valve-actuation portion 60on the right. The valve-cooling portion 58 has a helical groove 62formed in an inner surface thereof, and inlet and outlet grooves 64 and66, respectively, formed in an outer surface thereof. The inlet andoutlet grooves 64 and 66 are in communication with opposing ends of thehelical groove 62. The valve-actuation portion 60 has oil pressure slots68 and 70 formed therein. The oil path-defining piece 52 is insertedinto the circular bore 42 until a seat 74 on the oil path-defining piece52 contacts a seat on the cylinder block portion 36, and is preventedfrom further movement into the circular bore 42. An enclosed cavity isthen defined by the inlet groove 64 and a surface of the circular bore42. Similarly, cavities are defined by the outlet groove 66 and asurface of the circular bore 42 and by the oil pressure slots 68 and 70and surfaces of the circular bore 42.

The sleeve valve 54 is inserted from right to left into the oilpath-defining piece 52. The sleeve valve 54 has a sleeve portion 76 anda ridge component 78 around and close to a right end of the sleeveportion 76. An enclosed helical oil-cooling passage is defined by anouter surface of the sleeve portion 76, and by surfaces of the helicalgroove 62. Left and right surfaces 80 and 82, respectively, on the ridgecomponent 78 complete the cavities formed by the oil pressure slots 68and 70. The sleeve valve 54 is slidably movable to the right and back tothe left relative to the oil path-defining piece 52. An O-ring 84 islocated between the ridge component 78 and the valve-actuation portion60 to allow for sliding movement of the ridge component 78 relative tothe valve-actuation portion 60.

The retaining piece 56 is in the form of a ring having an outer diametersubstantially larger than the oil path-defining piece 52, and an innerdiameter that is only slightly larger than an outer diameter of thesleeve portion 76. The retaining piece 56 is located over a right end ofthe sleeve portion 76, so that a right end of the oil path-definingpiece 52 abuts against a left surface of the retaining piece 56. Theretaining piece 56 is then secured to the right casting 32 to retain theoil path-defining piece 52 in position. Bolts may be used to releasablysecure the retaining piece 56 to the right casting 32, to allow forremoval and maintenance of the oil path-defining piece and the sleevevalve 54. An O-ring 86 is located between an inner diameter of theretaining piece 56 and an outer surface of the right end of the sleeveportion 76, to allow for sliding movement of the sleeve portion 76 pastthe retaining piece 56. The O-ring 86 seals the cavity that is formed inpart by the right surface 82, one of the oil pressure slots 70, and anouter surface of the sleeve portion 76, so that oil cannot leaktherefrom, while still allowing for sliding movement of the sleeveportion 76 relative to the retaining piece 56.

The central connecting piece 34 is in the form of a ring having an outerportion 90 and an inner portion 92. The inner portion 92 has opposingside surfaces 94 that taper toward one another. A fuel supply cavity 96forms a volute within the inner portion 92 and around a horizontalcentral axis C of the central connecting piece 34. The centralconnecting piece 34 further includes spark plug sleeves 98, throughwhich spark plugs can be inserted through the fuel supply cavity 96without coming into contact with any fuel in the fuel supply cavity 96.

When the right casting 32 is mounted to the central connecting piece 34,an air inlet port 100 is defined between one of the side surfaces 94 onone side, and by end surfaces 102 and 104 of the cylinder block portion36 and the oil path-defining piece 52 on the other side. The air inletport 100 is a ring-shaped port around a horizontal central axis C of thesleeve valve 54. The air inlet port 100 extends from the outlet 48 ofthe air intake and distribution portion 38, and has a mouth 106 at aleft end of the sleeve portion 76. Movement of the sleeve valve 54 tothe right opens the mouth 106, and movement to the left closes the mouth106.

As shown in FIG. 3, a fuel outlet port 108 is formed from the fuelsupply cavity 96 through a wall of the inner portion 92. The sleeveportion 76 moves in a direction 110 to the right and to the left along aprimarily linear reciprocating path. The sleeve valve 54 is capable ofmoving in a perfectly linear path, although forces created by oil andfreedom of the sleeve valve 54 to rotate about a horizontal control axisC may cause slight rotation of the sleeve valve 54. An end surface 112of the sleeve portion 76 is at an angle 114 of approximately 45 degreesrelative to the direction 110. The inner portion 92 has a correspondingseat against which the end surface 112 abuts. When the end surface 112is against the seat of the inner portion 92, the fuel outlet port 108 isclosed. Movement of the sleeve portion 76 away from the seat opens thefuel outlet port 108. What should be noted is that the fuel outlet port108 is not mirrored on the left of the inner portion 92. Multiple fueloutlet ports, similar to the fuel outlet port 108, are formed in a ringaround a horizontal center line C of the inner portion 92.

In an alternate embodiment a fuel injector may be used to inject fueldirectly or air and fuel can be mixed externally. In such alternateembodiments water can be used within a cavity such as the cavity 96 forpurposes of cooling a sleeve valve.

Referring again to FIG. 1, the left casting 30 and left valvearrangement 14 are a mirror image of the right casting 32 and the rightvalve arrangement 16, respectively, with two notable structuraldifferences. First, as alluded to with reference to FIG. 2, a driveshaft opening such as the drive shaft opening 50 is not provided;instead, a circular bearing mounting is provided on each side of thecrankshaft mounting portion of the left casting 30. Second, the leftsleeve valve arrangement 14 does not control the flow of fuel out of thefuel supply cavity 96 because, as described with reference to FIG. 3,there are no fuel outlet ports on the left of the inner portion 92. Asdiscussed with reference to FIG. 2, an air inlet port 100 is formed onthe right of the central connecting piece 34. A similar constructionforms an air outlet port on the left of the central connecting piece 34.Typically the sleeve valve 54 over the exhaust port will not open as faras the air inlet port 100, because gas moves faster when it is hot. Itis also easier to cool the sleeve valve forming the exhaust if the portis shorter.

FIG. 1 shows three of four spark plugs 20 that are located around ahorizontal central axis C of the central connecting piece 34. FIG. 1also shows one of four spark plug openings 115 through which arespective spark plug 20 is inserted into the central connecting piece34. The respective spark plug 20 then passes through a respective one ofthe sleeves 98 shown in FIG. 2, and an electrode of the spark plugprotrudes from an inner surface of the inner portion 92. As shown inFIG. 4, one pair of the spark plugs 20 has electrodes 118A and 118Btogether at the top, and the other pair of the spark plugs 20 has theirelectrodes 118C and 118D together at the bottom. A positive high voltagemay, for example, be provided to the electrode 118A and a negative highvoltage to the electrode 118B, and a spark be created between theelectrodes 118A and 118B. Simultaneously, a positive high voltage can beprovided to the electrode 118C and a negative high voltage to theelectrode 118D to create a spark between the electrodes 118C and 118D.

FIG. 4 further illustrates an ignition system 250, including a voltagesupply 252, a switch 254 that is driven by a distributor or a computer,a primary winding 256, and a secondary winding 258. The voltage supply252, the switch 254, and the primary winding 256 are connected in seriesbetween two ground contacts 260 and 262. The secondary winding 258 islocated in a position to be induced by the primary winding 256, and isconnected between the electrodes 118A and 118B.

In use, the switch 254 connects the voltage supply 252 to the primarywinding 256, and creates a voltage over the primary winding 256. Thesecondary winding 258 is induced, so that a voltage is created over thesecondary winding 258. One end of the secondary winding 258 has apositive voltage, and an opposing end of the secondary winding 258 has anegative voltage.

High negative and positive voltages can be generated simply by havingone end of the secondary winding 258 connected to one electrode 118A,while the other end of the secondary winding 258 is connected to anotherelectrode 118B. The primary winding 256 operates normally between thesystem ground contacts 260/262 and the voltage supply 252. In this waythere are no high-voltage connections to the system ground contacts260/262. Additionally, the insulation requirements are reduced by half.For a given high-voltage delta between the electrodes 118A and 118B,only half that voltage is developed between either electrode (e.g.,118B) and the ground contact 260/262.

Reference is now made to FIGS. 1 and 5 in combination. In order not toobscure the drawings, not every detail in FIG. 1 is shown in FIG. 5, andnot every detail in FIG. 5 is shown in FIG. 1. In general, FIG. 1 showsonly general large assemblies, and FIG. 5 shows the components betterthat make up the larger assemblies.

The left power delivery arrangement 22 includes a left piston 120, aleft crankshaft 122, and a left connecting rod 124. The left crankshaft122 has opposing bearing sections 126 (the bearing sections 126 arelocated behind one another into the paper), an offset throw section 128,and connecting sections 130 that connect the offset throw section 128 tothe bearing sections 126. The bearing sections 126 are rotatably mountedon journal bearings (not shown) in the crankshaft housing 40 of the leftcasting 30. The entire left crankshaft 122 revolves about a leftcrankshaft axis through the bearing sections 126 that rotate on thejournal bearings.

The left piston 120 resides within the left casting 30, and is slidablymovable to the left and to the right on an inner surface of the sleevevalve 54 of the left valve arrangement 14. A left connecting pin 132 issecured to the left piston 120. The left connecting rod 124 has opposingends that are pivotably connected to the offset throw section 128 of theleft crankshaft 122, and to the left connecting pin 132. Rotation of theleft crankshaft 122 causes reciprocating movement of the piston 120 by adistance that equals two times a distance from the bearing sections 126to the offset throw section 128 of the left crankshaft 122.

Another embodiment may or may not have all the components of the leftpower delivery arrangement. A cam-based connection may, for example, beprovided. In a cam-based arrangement no connecting rod is provided and acam serves the purpose of moving a piston.

The combustion chamber size-varying mechanism 26 includes a train offirst, second, third, and fourth gears 134, 136, 138, and 140respectively, first and second gear shafts 142 and 144, respectively,and a combustion chamber size-varying carriage 146. The first gear 134is mounted to one bearing section 126 of the left crankshaft 122.Splines on the first gear 134 and the bearing section 126 of the leftcrankshaft 122 ensure that the first gear 134 does not slip on thebearing section 126 of the left crankshaft 122, and that the first gear134 thus rotates together with the left crankshaft 122. The first andsecond gear shafts 142 and 144 are rotatably mounted through respectivebearings to the base portion 28. The spatial relationship between thebearing sections 126 of the left crankshaft 122 and the first and secondgear shafts 142 and 144 is fixed, because they are all mounted to thesame base portion 28. The second and third gears 136 and 138 are mountedto and rotate with the first and second gear shafts 142 and 144,respectively. The second gear 136 meshes with the first gear 134, andthe third gear 138 meshes with the second gear 136. An effective workingdiameter of the first gear 134 is exactly two times an effective workingdiameter of the second gear 136, and the third gear 138 has the sameeffective working diameter as the second gear 136. The second gear 136also has exactly twice as many teeth as the first gear 134, and thethird gear 138 has the same number of teeth as the second gear 136. Thesecond and third gears 136 and 138 thus rotate at exactly half tirerotational speed of the first gear 134.

The combustion chamber size-varying carriage 146 has first and secondopposed ends 148 and 150, respectively. The first end 148 is pivotablysecured to the second gear shaft 144, so that the second end 150 canmove on a radius with a center point at the center line of the secondgear shaft 144.

The right power delivery arrangement 24 includes a right piston 154, aright crankshaft 156, and a right connecting rod 158. The right piston154 is located within and slides up and down the sleeve valve 54 in FIG.2. The right crankshaft 156 has opposing bearing sections 160, an offsetthrow section 162, and connecting sections 164 that connect the offsetthrow section 162 to the bearing sections 160. A right connecting pin166 is secured to the right piston 154. The right connecting rod 158 hasopposed ends that are pivotably secured to the right connecting pin 166and the offset throw section 162 of the right crankshaft 156. Thebearing sections 160 of the right crankshaft 156 are rotatably securedon respective journal bearings (not shown) to the combustion chambersize-varying carriage 146. The entire right crankshaft 156 can rotate ona right crankshaft axis through the bearing sections 160. Rotation ofthe right crankshaft 156 causes reciprocating movement of the rightpiston 154. A distance that the right piston 156 travels is equal to orclose to twice a distance from the crankshaft axis through the rightbearing sections 160 to an axis of the offset throw section 162.

An internal volume 170 is defined between facing surfaces of the leftand right pistons 120 and 154, and by inner surfaces of the centralconnecting piece 34 and the left and right valve arrangements 14 and 16.FIGS. 1 and 5 show the left and right crankshafts 120 and 156 rotated torespective angles so that the left and right pistons 120 and 154 are attheir farthest positions from the bearing sections 126 and 160,respectively, and the internal volume 170 is at its smallest. Pivotingof the combustion chamber size-varying carriage 146 through an angle 172rotates the bearing section 160 of the right crankshaft 156 through theangle 172 about the second gear shaft 144. Rotation of the bearingsection 160 of the right crankshaft 156 to the right causes movement ofthe right piston 154 to the right. Movement of the right piston 154 tothe right enlarges the internal volume 170. It should be noted that itis the combustion chamber, i.e., the minimum size of the internal volume170 that is enlarged, i.e., when the right crankshaft 156 is in anangular position wherein the right piston 154 is the farthest from thebearing section 160 of the right crankshaft 156. An enlargement of theminimum size of the internal volume 170 also causes a correspondingincrease in a maximum size of the internal volume 170.

The fourth gear 140 is mounted to the bearing section 160 of the rightcrankshaft 156 so as to rotate together with the right crankshaft 156.The fourth gear 140 meshes with the third gear 138. The fourth gear 140has exactly half the number of teeth of the third gear 138, and has aneffective diameter that is exactly half the effective diameter of thethird gear 138. The first and fourth gears thus rotate at the sameangular velocity, but in opposite directions. The pistons 120 and 154move away and toward one another. Movement of the pistons 120 and 154 isapproximately in phase, and the only difference in phase between thepistons 120 and 154 is small and due to pivoting of the combustionchamber size-varying carriage 146 through the angle 172.

FIG. 6 illustrates a valve-control system 174 that is used forcontrolling operation of the sleeve valve 54 of the right valvearrangement 16 shown in FIG. 2. The valve-control system 174 includes asupport structure 178, a valve-control carriage 180, first and secondcam drive gears 182 and 184, first and second followers 186 and 188, areturn spring arrangement 190, and a cam 192.

The valve-control carriage 180 has first and second ends 193 and 194,respectively. The first end 193 is pivotably secured to the first gearshaft 142 (see FIGS. 1 and 5). The first cam drive gear 182 is alsosecured to the first gear shaft 142, and is driven by the first gearshaft 142. The second cam drive gear 184 is rotatably secured to thevalve-control carriage 180. The first and second drive gears 182 and 184have the same effective diameter and have the same number of teeth, sothat they rotate at the same rotational speed of the second gear 136,and half the rotational speed of the left crankshaft 122 and the rightcrankshaft 156. One skilled in the art would thus appreciate that therotational speed of the second cam drive gear is correct for controllingfour-stroke operation. In an alternate embodiment each one of the gears182, 183, 136 and 138 may have a prime number of teeth to reduce wear.

The cam 192 is secured to and rotates with the second cam drive gear 184relative to the valve-control carriage 180. The support structure 178 isimmovably secured to the body 12 (see FIG. 1). The first follower 186 ismounted for linear translation movement to the support structure 178,and has a first end 195 against the cam 192. The return springarrangement 190 is mounted to an opposite end of the first follower 186,and to the support structure 178. The return spring arrangement 190provides a spring force that biases the first follower 186 toward thecam 192. The second follower 188 is mounted for linear translationmovement to the support structure 178 in a direction that is at 90degrees relative to a direction of travel of the first follower 186.

The cam 192 has an outer surface 196 with a profile, so that one cycleof the cam 192 causes one cycle of the first follower 186 back and forthon its linear path. The first follower 186 has a side surface 198 thatis profiled. An end of the second follower 188 rides on the side surface198. One cycle of the first follower 186 causes one cycle of the secondfollower 188 on its linear path.

Pivoting of the carriage 180 through an angle 200 rotates a center pointof the second cam drive gear 184 from a first position to a secondposition through the angle 200 relative to the support structure 178.The return spring arrangement 190 causes corresponding movement of thefirst follower 186 to the left, so that the end of the first follower186 remains in contact with the outer surface 196 of the cam 192.Rotation of the cam 192 still causes linear movement of the firstfollower 186 on a linear path. Movement of the carriage 180 through theangle 200 also moves the profile of the side surface 198 to the left.Because of movement of the profile of the side surface 198 to the left,the second follower 188 rides on a flat portion of the side surface 198for a longer period of time during a cycle of the first follower 186. Ascan be seen in FIG. 7, movement of the valve-control carriage 180 inFIG. 6 causes displacement of the second follower 188 for a shorterangle of rotation of the cam 192. What should also be noted is thatthere is a slight advancement in time of the phase of the secondfollower 188 relative to a phase of the first cam drive gear 182, whichis due to the second cam drive gear 184 that rolls in a clockwisedirection relative to a stationary position of the first cam drive gear182 upon clockwise pivoting of the valve-control carriage 180. The angleof the cam 192 at which the second follower 188 begins to move remainssubstantially unchanged, due to the phase change. The carriage 180 canalso be pivoted past its second position to a third position, so thatthe side surface 198 moves so far to the left that the second follower188 rides on the flat portion of the side surface 198 all the timeduring a complete cycle of the first follower 186.

The second follower 188 is connected through a hydraulic system (notshown) to the oil pressure slot 68 in FIG. 2, so that movement of thesecond follower 188 causes oil to flow into and out of the oil pressureslot 68. Because of the movement-limiting, phase-changing movement ofthe second follower 188, the movement and phase of the sleeve valve 54can be modulated. Modulation of the movement of the sleeve valve 54means that air intake through the air inlet port 100 and fuel intakethrough the fuel inlet port shown in FIG. 3 can be modulated.

Referring to FIG. 1, the left valve arrangement 14 serves merely as anexhaust. The internal combustion engine 10, in addition, to thevalve-control system 174 of FIG. 6, also has a valve-control system 174for controlling the left valve arrangement 14. However, because lesscontrol is required over exhaust, the valve-control system used forcontrolling the left valve arrangement 14 does not require movementlimiting or phase change of the sleeve valve of the left valvearrangement 14.

Full-power operation of the internal combustion engine is now described,primarily with reference to FIGS. 8A through 8G, and with the aid of allof the other figures heretofore described. During full-power operation,the combustion chamber size-varying carriage 146 in FIGS. 1 and 5 ispivoted clockwise to the right so that the right piston 154 is in thelocation of the phantom lines in FIG. 5 when the internal volume 170 isat its smallest. During full-power operation, the valve-control carriagein FIG. 6 is rotated counter-clockwise to the right.

FIG. 8A now illustrates the position of the left and right pistons 120and 154 at ignition and when the size of the internal volume 170 is atits smallest for full-power operation. Referring to FIG. 6, the end ofthe first follower 186 rides on a circular portion of the outer surface196 of the cam 192, and has thus not been displaced to the right. Thesecond follower 188 is in its uppermost position against the sidesurface 198. The sleeve valve 54 is maintained toward the left, whereinthe sleeve portions 76 close the air inlet port 100. Referring to FIG.3, the end surface 112 is against the seat on the inner portion 92, andcloses the fuel outlet port 108. With further reference to FIG. 8A, asleeve valve 54 of the left valve arrangement 14 closes an exhaust port202. The internal volume 170 is filled with pressurized air and fuel,typically vaporized petroleum. Referring to FIG. 4, a current isprovided to the electrodes 118 of the spark plugs 20, which ignites thefuel. Ignition causes combustion, and an increase in pressure within theinternal volume 170. The increased pressure moves the left piston 120 tothe left, and the right piston 154 to the right.

FIG. 8B illustrates the left and right pistons 120 and 154 after the endof expansion of the internal volume 170 due to the increased pressure ofcombustion. The expansion causes a reduction in pressure and temperaturewithin the internal volume 170. With reference to FIG. 5, expansion ofthe internal volume 170 causes rotation of the left crankshaft 122 in aclockwise direction, and rotation of the right crankshaft 156 in acounterclockwise direction. A force that is generated through theconnecting rod 122 creates a clockwise torque on the bearing sections126. An extension of one of the bearing sections 126 can form an outputshaft through which the torque can be delivered to a drive train. Aforce created by the right connecting rod 158 creates a counterclockwisetorque on the right bearing section 160. The torque created on the rightbearing section 160 is provided to the fourth gear 140. Thecounterclockwise torque on the fourth gear 140 is provided through thethird and second gears 138 and 136 sequentially as a clockwise torque onthe first gear 134. The clockwise torque created on the first gear 134is provided to the first bearing section 126 and added to the torque dueto the left connecting rod 124.

FIG. 8C illustrates the left and right pistons 120 and 154 midwaythrough exhaust. The sleeve valve 54 of the left valve arrangement 14has been moved to the left to open the exhaust port 202. The internalvolume 170 reduces in size, and combusted gas discharges through theexhaust port 202.

FIG. 8D shows the left and right pistons 120 and 154 at the end ofexhaust. The internal volume 170 is again at its smallest size for fullpower operation. The sleeve valve 54 of the left valve arrangement 14 ismoved to the right to close the exhaust port 202.

FIG. 8E illustrates the position of the left and right pistons 120 and154 and the position of the sleeve valves 54 early in the intake stroke.The left piston 120 has moved to the left by a small distance, and theright piston 154 has moved to the right by a small distance. Referringto FIG. 6, the shape of the outer surface 196 of the cam 192 has movedthe first follower 186 to the right by a small distance, and the sidesurface 198 of the first follower 186 has moved the second follower 188down by a small distance. Referring to FIG. 2, downward movement of thesecond follower 188 of FIG. 6 has caused oil to flow into the oilpressure slot 68 on the left, and oil to flow out of the oil pressureslot 70 on the right. To compensate for a possible increase in pressureon the left surface 80 compared to a pressure on the right surface 82,the sleeve valve 54 has moved to the right by a small distance. The airinlet port 100 is now open by a small amount. Fuel is provided through afuel opening (not shown) into the fuel supply cavity 96 and, referringto FIG. 3, the end surface 112 is moved to the right to open the fueloutlet port 108. The fuel is allowed to flow from the fuel supply cavity96 through the fuel outlet port 108. Referring again to FIG. 8E, air andfuel enter into the internal volume 170. As shown in FIG. 8F, the leftand right pistons 120 and 154 continue to move to the left and right,respectively. Referring to FIG. 6, the cam 184 is now in the illustratedposition, wherein the first and second followers 186 and 188 have beendisplaced to their maximum. Referring again to FIG. 8F, the air inletport 100 is now open to its maximum. The position illustrated in FIG. 8Fcorresponds to a peak 204 in FIG. 7.

FIG. 8G illustrates the left and right pistons 120 and 154 at the end ofintake. The pistons 120 and 154 have moved their maximum distances orstrokes to the left and right, respectively. Referring to FIG. 6, thecam 192 has rotated so that the first follower 186 is again on acircular portion of the outer surface 196 and thus at its maximumposition to the left for full-power operation. The second follower 188is also at its uppermost position. Referring again to FIG. 8G, thesleeve valve 54 of the right valve arrangement 16 closes the air inletport 100 and, referring to FIG. 3, closes the fuel outlet port 108.

The expansion stroke of FIG. 8B imparts angular momentum to flywheelsconnected to the left and right crankshafts 120 and 156 shown in FIG. 5.The momentum of the flywheels moves the left and right pistons 120 and154 through the sequence illustrated in FIGS. 8C through 8G. Themomentum then moves the left and right pistons 120 and 154 from theirpositions to the position illustrated in FIG. 8A, thereby reducing thesize of the internal volume 170 and compressing the air within theinternal volume 170.

Partial-power operation is now illustrated, primarily with reference toFIGS. 9A through 9G, and with the aid of the other figures heretoforedescribed. With reference to FIG. 5, partial power operation is when thecombustion chamber size-varying carriage 146 is rotated through theangle 172 counterclockwise to the left. Referring to FIG. 6, duringpartial-power operation, the valve-control carriage 180 is rotatedthrough the angle 200 clockwise so that the components are in theposition illustrated by the phantom lines.

When comparing FIGS. 9A and 8A, it can be seen that the internal volume170 during ignition is much smaller for partial power than for fullpower. When comparing FIGS. 9B and 8B, it will show that a maximum sizeof the internal volume is also smaller during partial-power operationthan during full-power operation. FIGS. 9C and 9D show the positions ofthe left and right pistons 120 and 154 during exhaust and at the end ofexhaust, respectively. The internal volume in FIG. 9D is smaller thanthe internal volume in FIG. 8D.

FIG. 9E illustrates the position of the left and right pistons 120 and154 early during the intake stroke. The sleeve valve 54 of the rightsleeve arrangement 16 has opened by a small amount. Referring to FIG. 6,the cam 192 has been rotated to deflect the first follower 186 by amaximum distance for partial-power operation, and to deflect the secondfollower 188 by a maximum distance for partial-power operation.Referring to FIG. 7, the distance that the sleeve valve 54 of the rightsleeve arrangement 16 is displaced is reflected by comparing the heightof the peak 204 to the height of the peak 206. It should also be notedthat, although FIGS. 9E and 8E appear to be similar, there is in fact anadvancement of the phase from the peak 204 to the peak 206, so thatmaximum opening of the air inlet port 100 only occurs in FIG. 8F duringfull-power operation, whereas maximum opening of the air inlet port 100occurs in FIG. 9E during partial-power operation.

FIG. 9F illustrates the positioning of the left and right pistons 120and 154 midway through intake. Referring to FIG. 6, the first follower186 is not yet on the circular portion of the outer surface 196 of thecam 192, but the second follower 188 is still at its uppermost position.Referring again to FIG. 9F, the sleeve valve 54 of the right sleevearrangement 16 closes the air inlet port 100, and referring to FIG. 3,the fuel outlet port 108 is also closed. Referring to FIG. 9G, the leftand right pistons 120 and 154 continue to move to the left and to theright respectively, while the sleeve valves 54 are closed. Enlargementof the internal volume 170 causes a slight decrease in pressure. Whenthe left and right pistons 120 and 154 begin to return toward oneanother, the pressure within the internal volume 170 again returns tothe pressure of the internal volume 170 in FIG. 9F. The left and rightpistons 120 and 154 then return to their position shown in FIG. 9A forpurposes of ignition.

Referring to FIG. 2, heat that is generated in the combustion process isillustrated with reference to FIGS. 8A to 8G and 9A to 9G may causeoverheating of the sleeve valve 54. An oil inlet port (not shown)through the cylinder block portion 36 is connected to the inlet groove64 and a similar oil outlet port is connected to the outlet groove 66. Acooling fluid in the form of cooling oil is pumped through the oil inletport and out of the oil outlet port. The cooling oil flows through thehelical groove 62 over an outer surface of the sleeve portion 76. Heatconvects from the sleeve portion 76 to the cooling oil, and is removedby the oil through the oil outlet port. Oil flow is from left to right,which ensures that the oil is as cool as possible closer to the left ofthe sleeve valve 54, although oil flow can be reversed to reducepressure at the inlet groove 64 if it is found that oil leaksexcessively past the left of the sleeve valve 54. Referring to FIG. 3,fuel circulating through the fuel supply cavity 96 cools the seat 74that the end surface 112 comes into contact with.

One advantage of the invention is that energy losses are minimized inall modes. With reference to FIGS. 1, 2, and 5, it can be seen that theinternal volume 170 is entirely defined by inner surfaces of the sleeveportions 76 of the left and right valve arrangements 14 and 16, an innersurface of the inner portion 92, and facing surfaces of the left andright pistons 120 and 154. A volume of the internal volume 170 is thusapproximately the area of the left piston 120 multiplied by a distancebetween the facing surfaces of the left piston 120 and the right piston154. It is also within the scope of the invention that the internalvolume 170 be slightly larger than the surface area of the face of theleft piston 120 multiplied by the distance between the facing surfacesof the left and right pistons 120 and 154, for example 20% larger, morepreferably 10% larger when the left and right pistons 120 and 154 are attheir maximum stroke. Because of the facing relationship of the left andright pistons 120 and 154, there is no cylinder head for the left piston120 through which heat can escape, nor is there a cylinder head for theright piston 154 through which heat can escape. The facing relationshipbetween the left and right pistons 120 and 154 thus assists incontainment of heat energy, with a corresponding increase in efficiency.

What should also be noted is that the left and right pistons 120 and 154have relatively small diameters compared to the volume of the internalvolume 170. The relatively low surface area to volume ratio furtherassists in reducing heat losses. A reduction in surface area of a pistonnormally corresponds with an increase in the stroke of the piston inorder to obtain the same displacement, but because left and right powerdelivery arrangements 22 and 24 are provided, the stroke of each piston120 or 154 is approximately half of what would be required if only asingle piston is provided. Because of the relatively short stroke lengthof, for example, the left piston 120, it can run at higher revolutionsper minute and produce more power than in an arrangement where only asingle piston is provided.

The extra heat that is contained with the facing relationship betweenthe left and right pistons 120 and 154 can be extracted more efficientlyin the partial-power operation of FIGS. 9A through 9G. In all low heatloss engines such as this, energy that is transferred through a pistonto a drive train and energy losses in an exhaust of gas in an exhaustcycle together are more than 65%, more preferably more than 70% and morepreferably more than 75% of the energy of the fuel.

What should be noted specifically with reference to FIGS. 9E through 9Gis that the gas within the internal volume 170 expands to its maximum.As mentioned previously, expansion of the gas within the internal volume170 causes cooling of the gas. Maximum expansion thus results in maximumcooling of the gas in the internal volume 170 and maximum extraction ofheat from the gas. When the gas is exhausted, it is relatively coolcompared to an arrangement having no variable compression and running atpartial power. What should also be noted is that expansion andcompression is asymmetric similar to the Atkinson Cycle or the MillerCycle. A synergistic effect is created by the combination of low heatloss and asymmetric expansion.

FIG. 10A illustrates a hydraulic system 208 that is used to provide avarying amount of high pressure within the oil pressure slot 70 so thatthe sleeve valve 54 keeps the air inlet port 100 closed. As can furtherbe seen in FIG. 10A, the second follower 188 of FIG. 6 is connectedthrough a hydraulic connection system 210 to the oil pressure slot 68.The hydraulic connection system 210 ensures that translation of thesecond follower 188 causes corresponding translation of the sleeve valve54.

The hydraulic system 208 includes a valve-pressure cylinder 212, avalve-pressure piston 214, and a valve return spring 216. Thevalve-pressure cylinder 212 and the valve-pressure piston 214 jointlyform a valve-pressure reservoir 218 with the valve-pressure piston 214forming a side piece of the valve-pressure reservoir 218. The valvereturn spring 216 is located outside the valve-pressure reservoir 218against the valve-pressure piston 214.

The hydraulic system 208 further includes a high-pressure reservoir 220.The high-pressure reservoir 220 holds oil at a pressure higher than apressure in the valve-pressure reservoir 218 when the valve is closed.

The high-pressure reservoir 220 and the valve-pressure reservoir 218 areconnected through a rotating valve 222 to the oil pressure slot 70. Inthe position shown in FIG. 10A, the valve 222 connects the high-pressurereservoir 220 to the oil pressure slot 70, and tire valve-pressurereservoir 218 is disconnected from the oil pressure slot 70. In thisstate, the sleeve valve 54 is prevented from movement that would openthe air inlet port 100, in particular due to piston friction.

In FIG. 10B, the valve 222 is rotated so that it connects thevalve-pressure reservoir 218 to the oil pressure slot 70, anddisconnects the high-pressure reservoir 220 from the oil pressure slot70. Due to the lower pressure in the valve-pressure reservoir 218compared to the high-pressure reservoir 220, the sleeve valve 54 ispermitted to open the air inlet port 100. The second follower 188,accordingly, moves into a position wherein the sleeve valve 54 opens theair inlet port 100. Movement of the sleeve valve 54 causes oil to flowout of the oil pressure slot 70 through the valve 222 into thevalve-pressure reservoir 218 against a force created by the spring 216.Energy is stored in the spring 216. The energy stored in the spring 216moves some of the oil back into the oil pressure slot 70. Flow of oilinto the oil pressure slot 70 and out through the slot 68 creates apressure differential between the surfaces 82 and 80, which causes thesleeve valve 54 to close the air inlet port 100. No work is done by theoil of the reservoir 220 when moving between the configurations in FIGS.10A and 10B, because the valve 222 is only actuated to open to thehigh-pressure reservoir 220 when the sleeve valve 54 is closed, in thatway, no oil needs to flow, yet the pressure is high.

FIG. 11 shows a control system forming part of the engine of FIG. 1,including the combustion chamber size-varying carriage 146, thevalve-control carriage 180, a combustion chamber size-varying actuator230, a valve-control actuator 232, a knock sensor 234, and a computersystem 236.

The knock sensor 234 is connected to the body 12 shown in FIG. 1 and candetect pre-ignition due to over-compression. The computer system 236 isconnected to the knock sensor 234 so that the knock sensor 234 providesa signal to the computer system 236 indicating pre-ignition or nopre-ignition.

The computer system 236 has a processor and memory. A set ofinstructions and a data map are stored in the memory. The set ofinstructions is executable by the processor so that the processor canprovide a selected output. The set of instructions also interacts withthe data file to vary a response from the computer system 236.

The combustion chamber size-varying actuator 230 and the valve-controlactuator 232 are mounted to the combustion chamber size-varying carriage146 and the valve-control carriage 180, respectively. The actuators 230and 232 are connected to the computer system 236 and are under thecontrol of the computer system 236. The computer system 286 controls theactuators 230 and 282 based on pre-ignition detected by the knock sensor234. In particular, should pre-ignition be detected by the knock sensor234, the computer system 236 adjusts the map. The computer system 236utilizes the map to operate the combustion chamber size-varying actuator230, so that the combustion chamber size-varying carriage 146 is movedto increase the minimum size of the volume within the engine forming theinternal volume. An increase in the size of the internal volume resultsin a corresponding lowering of the compression ratio.

The combustion chamber size-varying carriage 146 thus serves the dualpurpose of reducing the size of the volume forming the internal volume170, as discussed with reference to FIGS. 9A to 9G, to reduce thecompression ratio in the event of pre-ignition. The feature of varyingthe compression ratio based on pre-ignition is useful because it allowsfor different fuel types to be used. Should a switch, for example, bemade from a high-octane fuel to a low-octane fuel, the knock sensor 234would detect pre-ignition, and the compression ratio would be reduced bythe combustion chamber size-varying carriage 146. The computer system236 receives input from additional sensors 238, and bases its responsealso on the additional sensors 238. The additional sensors 238 may, forexample, be sensors for detecting engine load, engine revolutions perminute, air temperature, water temperature, oil temperature, fueltemperature, altitude, etc. The system also allows for the use ofalternate fuels such as methane, propane, ethanol, hydrogen, or othervolatile flammable fuels.

One variation to the embodiments hereinbefore described is to havemechanical valve operation instead of the hydraulic valve operationdescribed primarily with reference to FIG. 2. In a mechanical valveoperating system, a fork can, for example, be connected directly to asleeve valve, and the fork can be moved with a valve-control system suchas the valve-control system 174 in FIG. 6.

In an alternative embodiment, it may also be possible to replace thehydraulic hold-closed system 208 of FIGS. 10A and 10B with a mechanicalhold-closed system. In the mechanical hold-closed system, a spring canbe located within the right casting 32, and act on a flange that isconnected to a sleeve valve such as the sleeve valve 54.

Chain and toothed belt drives have been developed that transfer powermore efficiently than gear meshes such as between the gears 134, 136,138 and 140 of FIG. 1. A challenge with the use of a closed loopelongate member such as a chain or a tooth belt is to keep it properlytensioned. FIGS. 12A and 12B illustrate components of a combustionchamber size-varying mechanism 250 that can be used instead of thecombustion chamber size-varying mechanism 26 of FIG. 1. The two crankshafts 126 and 160 are connected to one another with four linkagesconnected to one another in the form of a parallelogram mechanism. Theparallelogram mechanism formed by the linkages 252 has pivot points 254at juxtaposed corners and pivot points 256 at juxtaposed corners. Thepivot points 256 coincide with the bearing sections 126 and 160 of thecrank shafts.

A respective idler roller or gear 260 is connected at a respective oneof the pivot points 254 and 256. A flexible elongate member 262 formedinto a closed loop runs sequentially from one of the idler rollers orgears 260 to the next. The flexible elongate member 262 may for examplebe a chain or a toothed belt. The idler rollers or gears 260 all havethe same diameter, so that sections of the elongate member 262 extendingfrom one of the idler rollers 260 to the next always has the same lengthas one of the links 252. A change of the parallelogram from thearrangement shown in FIG. 12A to the arrangement shown in FIG. 12B willcause a reduction in an arc that the elongate member 262 contacts one ofthe idler rollers 260 at one of the pivot points 254 and a correspondingincrease in an arc that the elongate member 262 contacts one of theidler rollers 260 at one of the pivot points 256. The elongate member262 thus always remains fully tensioned. Additionally and moreimportantly, the mechanism that is used for tensioning the elongatemember 262 insures that the two crank shafts stay in the same relativephase as they are moved closer and farther apart.

In one example engine configuration, the minimum crank shaft spacing is16 inches and the maximum spacing is 17 inches. Choosing the links 252to be approximately 9 inches long, would cause the spacing of the idlerrollers or gears 260 to be approximately 8 inches apart when the crankshafts are closest to one another and about 5.5 inches apart when thecrank shafts are spaced 17 inches from one another.

Because the motion of the idler gears 260 is symmetric about a centerline between the two crank shafts, both top and bottom sections of theelongate flexible member 262 are displaced the same amount, leaving themoving crank shaft and the fixed crank shaft at the same relativerotational angle. It is important to keep the links 252 the same lengthand the idler gears or rollers 260 the same diameter so that there isalways the same amount of chain between each pair of idler gears orrollers 260.

It is likely that an additional idler roller or gear may be necessary totake up a very small amount of belt or chain tolerance in the elongatemember 262 near the fixed crank shaft. This such an additional idlerroller or gear would be used to account for manufacturing tolerances andwear in the elongate member 262. If tire elongate member 262 is a chain,or stretch in the elongate member 262 if the elongate member 262 is abelt.

FIGS. 13A and 13B illustrate components of a combustion chambersize-varying mechanism 270 according to a further embodiment of theinvention. The mechanism 270 includes four rollers or gears 272, 274,276 and 278, and elongate member 280, and two sensors 282 and 284. Thesensors 282 and a controller are used to keep the mechanism 270 simple.The elongate member 280 forms a closed loop over the rollers or gears272 and 274. Bearing portions 126 and 160 can be adjusted relative toone another. The idler roller or gear 276 has an arbitrary size and ismounted on an actuator 286.

A position of the actuator 286 is controlled by a computer. The sensors282 and 284 detect angles of the bearing sections 126 and 160 andprovide the angles as feedback to the computer. The computer adjusts theactuator 286 based on a difference between the angles measured by thesensors 282 and 284.

As the bearing section 160 begins to get out of phase relative to thebearing section 126, during a change in compression ratio, the actuator286 moves the idler roller or gear 276. Movement of the idler roller orgear 276 increases or decreases a length of the elongate member 280 onone side of the closed loop relative to the other side of the closedloop. Such adjustment of the elongate member 280 brings the bearingsections 126 and 160 to the desired phase angle relative to one another.The other side of the elongate member 280 is tensioned in a normalmanner with the idler roller or gear 278 with either spring 288, air orhydraulic force supplied to keep the elongate member 280 tight.

The advantage of the systems of FIGS. 12A and B and 13A and B is thatthe crank shafts corresponding to the bearing sections 126 and 160 canbe maintained exactly in phase to insure that the vibration level of theengine will remain minimal. When the crank shafts are in phase, thesystem is naturally balanced. An additional advantage of the mechanismsof FIGS. 12A and B and 13A and B is that they allow for more arbitrarymotion of the movement of the crank shafts. This added flexibility ofthe crank shaft motion control allows for much more simple mechanismsand for much more rigid structures to hold them.

In the arrangement of FIG. 2, an O-ring 300 is located within an innergroove at an end of the oil path-defining piece 52. The O-ring 300 hasan outer, front and rear surfaces that seal with groove. An innersurface of the O-ring 300 is located against an outer surface of thesleeve portion 76. The sleeve portion 76 can slide relative to theO-ring 300. The O-ring 300 prevents oil within the inlet groove 64 frompassing over the outer surface of the sleeve portion 76 into the airinlet port 100. Over time it may happen that the O-ring 300 begins towear, in which case oil will enter through the air inlet port 100 intothe combustion chamber, which can lead to excessive smoking of theengine.

FIG. 14 illustrates an arrangement that is similar to the arrangement ofFIG. 2, except that the O-ring 300 and the oil inlet port of thearrangement of FIG. 2 are not provided in the arrangement of FIG. 14.Instead, a flexible bellows seal 302 is provided. The seal 302 has frontand rear ends 304 and 306. The front end 304 is mounted to an end of thesleeve portion 76 and moves together with the sleeve portion 76 in areciprocating manner. The rear end 306 is mounted to the casing 32 andremains stationary together with the casing 32 upon movement of thesleeve portion 76. Because of the alternating bellows shape of the seal302 between the front and rear portions 304 and 306, the seal 302 issufficiently flexible to allow for relative movement of the front end304 relative to the rear end 306. The seal 302 may also have a springconstant that assists in closing the sleeve portion 76.

An inner surface of the seal 302 together with the end surface 102define an oil outlet port 308. Oil flowing over an outer surface of thesleeve portion 76 enters the oil outlet port 308. The oil issubsequently cooled and recirculated into an oil inlet port 310. Thisseal 302 thus prevents the oil from entering into the combustionchamber.

An outer surface of the seal 302 together with the side surface 94define an air inlet port 100. The seal 802 thus does not prevent airfrom flowing through the air inlet port 100 into the combustion chamber.

What should further be noted is that a lip 312 is provided at an end ofthe sleeve portion 76. The lip 312 has a tapered inner surface on a sidefacing the piston 154 and thus on a side opposite to the centralconnecting piece 34. When the piston 154 compresses air within thecombustion chamber, with the sleeve portion 76 in a closed position, apositive pressure differential is created between inner and outersurfaces of the lip 312. The positive pressure differential furtherassists in keeping the lip 312 closed against the central connectingpiece 34. The piston 154 has a front surface 320 with a tapered edge322. The tapered edge 322 has a shape that is complementary to a shapeof the inner surface of the lip 312 so that the lip 312 does not inhibitmovement of the piston 154.

Although a bellows type seal 302 is described, it should be understoodthat another type of flexible seal may be used instead of a bellows typeseal. A cone type spring arrangement can, for example, be used as a sealor two or more of such cone type seal arrangements can be stacked ontoone another in back-to-back fashion. It may also be possible to form adiaphragm out of steel or another metal that can tolerate the thermalstresses of the engine.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative and not restrictive of the current invention, andthat this invention is not restricted to the specific constructions andarrangements shown and described since modifications may occur to thoseordinarily skilled in the art. Some of the technologies described may,for example, find application in rotary engines, engines having only asingle crankshaft, engines having poppet valves, engines havingelectrically controlled valve actuation, engines having external mixingof fuel and air, engines having more than one piston connected to onecrankshaft, etc.

1. An internal combustion engine, comprising: a body defining acylinder; a piston in the cylinder, a front surface of the piston and awall of the cylinder defining an internal volume; a port in the body toallow air and fuel into the internal volume; a sleeve valve at leastpartially around the piston having an exterior surface and a distal end,the sleeve valve being movable between a first position where the portis open and a second position where the sleeve valve closes the port; anoil path-defining piece adjacent to the exterior surface of the sleevevalve, wherein surfaces of the oil path-defining piece and the exteriorsurface of the sleeve valve define an oil passage; an oil inlet portthrough the body into the oil passage; an oil outlet port from the oilpassage through the body; and a flexible seal having a first end affixedto the body and a second end affixed to the exterior surface of thesleeve valve.
 2. The internal combustion engine as recited in claim 1,wherein the flexible seal is a bellows seal.
 3. The internal combustionengine as recited in claim 2, wherein the bellows seal has an interiorsurface and an exterior surface.
 4. The internal combustion engine asrecited in claim 3, wherein the oil outlet port is partially defined bythe inner surface of the bellows seal.
 5. The internal combustion engineas recited in claim 3, wherein the port in the body to allow air andfuel into the internal volume is partially defined by the exteriorsurface of the bellows seal.
 6. The internal combustion engine asrecited in claim 2, wherein the bellows seal prevents oil travellingthrough the oil passage from entering into the internal volume.
 7. Theinternal combustion engine as recited in claim 2, wherein the bellowsseal assists in moving the sleeve valve from the first position to thesecond position.
 8. The internal combustion engine as recited in claim2, wherein the bellows seal assists the sleeve valve maintain the secondposition.
 9. The internal combustion engine as recited in claim 2,wherein the second end of the bellows seal is affixed proximate to thedistal end of the sleeve valve.
 10. The internal combustion engine asrecited in claim 2, wherein the bellows seal prevents oil travellingthrough the oil passage from entering the port that allows air and fuelinto the internal volume.
 11. The internal combustion engine as recitedin claim 1, wherein the flexible seal is a cone-shaped seal.
 12. Aninternal combustion engine, comprising: a body defining first and secondcylinders in communication with each other; first and second pistons inthe first and second cylinders respectively, front surfaces of the firstand second pistons and walls of the first and second cylinders definingan internal volume; a first port in the body to allow air and fuel intothe internal volume; a second port in the body to allow exhaust gas outof the internal volume; a first sleeve valve at least partially aroundthe first piston, the first sleeve valve being movable between a firstposition where the first port is open and a second position where thefirst sleeve valve closes the first port; a second sleeve valve at leastpartially around the second piston, the second sleeve valve beingmovable between a first position where the second port is open and asecond position where the second sleeve valve closes the second port; anoil path-defining piece adjacent the first sleeve valve, whereinsurfaces of the oil path-defining piece and the sleeve valve define anoil passage; an oil inlet port through the body into the oil passage; anoil outlet port from the oil passage through the body; and a bellowsseal having a first end affixed to the body and a second end affixed tothe first sleeve valve.
 13. The internal combustion engine as recited inclaim 12, wherein the bellows seal prevents oil travelling through theoil passage from entering into the internal volume.
 14. The internalcombustion engine as recited in claim 12, wherein the bellows sealassists in moving the first sleeve valve between the first position andthe second position.
 15. The internal combustion engine as recited inclaim 12, wherein the bellows seal assists the first sleeve valvemaintain the second position.
 16. The internal combustion engine asrecited in claim 12, wherein the second end of the bellows seal isaffixed proximate to a distal end of the first sleeve valve.
 17. Theinternal combustion engine as recited in claim 12, wherein the bellowsseal prevents oil travelling through the oil passage from entering thefirst port.
 18. The internal combustion engine as recited in claim 12,wherein the bellows seal includes an inner surface and an outer surface.19. The internal combustion engine as recited in claim 18, wherein theinner surface of the bellows seal prevents oil travelling between theoil passage and the oil outlet port from entering the first port. 20.The internal combustion engine as recited in claim 18, wherein the outersurface of the bellows seal partially forms the first port.